1. Examine this infographic (Home cooling 101) on Energy Saver, a website of the US Department of Energy.
(You can download the pdf version here.)
You are invited to explore the website : lots of interesting information are to be found there.
2. Watch this video (How a central air conditioner works) on the RepairClinic YouTube channel (vidéo à préparer pour le 3 mars jusqu’à la minute 3:30; vous recevrez la transcription le 3 mars). (voir màj ci-dessous)
You might compare it with How my air conditioner works, on the same channel.
(What’s the difference between the two systems ?)
The whole RepairClinic website should be of interest to you.
3. Just for fun… Fixing an air conditioner can be a dangerous job !
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Mise à jour : Transcript
NB : les mots soulignés sont ceux qui sont mal transcrits dans les sous-titres (CC)
Although central air conditioners differ from model to model,
they operate on similar principles.
In this video we will address how central air conditioners work
as well as potential problems you may encounter.
Included among the components that make up a central air system
is a condensing unit which is located outside the home.
The condensing unit contains the air conditioner condenser coils,
the compressor and the condenser fan motor.
The evaporator coils, or cooling coils, are located inside the home
and are mounted on top of a furnace or air handler.
0:47 The furnace or air handler uses a circulation blower fan
to drive air through the return vent,
blow it past the evaporator coils
and force the air to the home’s venting.
The room air is then drawn back through the return
and the air flow cycle continues.
Once the room air has cooled sufficiently,
the wall thermostat signals the circulation blower fan and condensing unit to turn off
until the room temperature increases.
1:13 This process can be broken down into three main factors :
temperature control, cooling, and air circulation.
The temperature in the home is regulated by the wall thermostat.
The thermostat can be powered by the furnace control board
or by batteries.
The thermostat must be in a central location in the home
positioned at high level and away from direct sunlight
for proper temperature regulation.
1:43 When the thermostat detects an increase in temperature
it closes the cooling circuit,
allowing voltage to travel to the control board.
The control board uses a time sequence
to send 120V of alternating current
to the circulation blower fan motor in the furnace
and 24V to the condensing unit contactor.
When the condensing unit contactor is energized,
it allows 240V to flow to a nearby disconnect box,
to the compressor and the condenser fan motor.
The disconnect box,
which provides a way to turn off power to the condensing unit outside,
includes a cartridge which may contain fuses.
If the compressor and condenser fan motor fail to work,
the disconnect box fuses can tested for continuity
to determine if a continuous electrical path is present.
2:33 The compressor acts as a pump,
compressing refrigerant in gas form into the condenser coils
where the gas is condensed into a hot liquid.
The condenser coils dissipate the heat as the liquid travels through them
and a fan is used to assist the coils in this process.
Once the refrigerant has passed through the condenser coils,
it travels to the evaporator coils located on the furnace or air handler.
As the refrigerant liquid enters the coils it expands into a gas
which makes the coils cold.
The gas flows through the coils to a suction line attached to the compressor.
The compressor converts the gas back into a liquid
and the cooling cycle continues.
3:15 The humidity in the air condenses on the cold evaporator coils
and drips down into a set of collection trays.
The trays are attached to either a condensate pump or a floor drain.
It’s important to keep the condenser clean.
3:31 If leaves or other debris clog the coils,
the heat will not be dissipated properly
and the system will not function efficiently.
You can use a garden hose to clean the condenser
by spraying the coils from the inside out.
The most important factor in efficient operation is airflow.
To ensure proper airflow, the air filter should be checked monthly
and replaced as needed.
There are several types of filters available
and range from 1 to 5 inches thick.
The filters can be installed into the slot in the return
or in an air cleaner.
Some homes will have an electronic air filter,
which is powered by the furnace or air handler control board
when the circulation blower fan turns on.
4:19 The blower fan motor can run at multiple speeds to improve efficiency.
Lower speeds are used when the furnace is heating
and higher speeds are used for air conditioning.
If the circulation blower fan becomes noisy during use,
the set screw on the blower wheel may have loosened,
causing the wheel to wobble on the motor shaft.
You can fix this problem by tightening or replacing the screw
or replacing the blower wheel altogether.
4:47 RepairClinic has a solution
for many of the problems you may be experiencing with your central air system.
To find a complete list of compatible parts,
you should enter the appropriate model number in our website seach engine.
Keep in mind that the condensing unit and furnace
will have separate model numbers.
To find parts such as the circulation blower fan motor or control board,
you will need to enter the furnace model number.
to fnd a contactor or condensr fn motor,
the model number found on the condensing unit will be required.
Our site also has an extensive selection of instructional videos
to assist you, covering topics like part testing, disassembling
and part replacement.
At RepairClinic, we make fixing things easy.
